One signature for creating unit tests that run on premade GrContexts

tests/GrSurfaceTest.cpp

Index: tests/GrSurfaceTest.cpp
diff --git a/tests/GrSurfaceTest.cpp b/tests/GrSurfaceTest.cpp
index ac0b399b69c0a6e1fa583ab3f7b743ff3c9e6eb6..280a1c8a724014833d26ecebfa611d239697174d 100644
--- a/tests/GrSurfaceTest.cpp
+++ b/tests/GrSurfaceTest.cpp
@@ -18,7 +18,8 @@
 
 // Tests that GrSurface::asTexture(), GrSurface::asRenderTarget(), and static upcasting of texture
 // and render targets to GrSurface all work as expected.
-DEF_GPUTEST_FOR_NULL_CONTEXT(GrSurface, reporter, context) {
+DEF_GPUTEST_FOR_NULL_CONTEXT(GrSurface, reporter, ctxInfo) {
+    GrContext* context = ctxInfo.fGrContext;
     GrSurfaceDesc desc;
     desc.fConfig = kSkia8888_GrPixelConfig;
     desc.fFlags = kRenderTarget_GrSurfaceFlag;